CCPP: Cross-Chain Privacy-Preserving for CCLS With Lattice-Based Ring Signature

Cold chain logistics systems (CCLSs) require the secure, efficient, and fresh management of cold products. Blockchain technology facilitates cross - institutional data - sharing for CCLSs, yet heterogeneous blockchains across different institutions give rise to ’data islands’ and privacy issues. Facing these problems,we propose a cross-chain privacy-preserving (CCPP) framework based on a notary mechanism. This CCPP model aggregates heterogeneous institutional chains through a notary network, enabling inter-blockchain operability while eliminating the data islands. Meanwhile, to ensure transaction security and address the quantum-vulnerability of traditional signature schemes, we design an identity-based ring signature (ID-RS) scheme. The ID - RS combines the identity mechanism (for traceability) with the ring mechanism (to guarantee the signer’s unconditional anonymity), and combats quantum threats by relying on the lattice assumption (a foundation for post-quantum security). Under the random oracle model, we prove the correctness, unforgeability, and anonymity of the ID-RS scheme. Additionally, experimental results under 80-bit security settings show that our ID-RS scheme outperforms other signature schemes in signature size and verification latency. These findings validate that the CCPP framework and the ID-RS scheme together offer an efficient and practical foundation for privacy-preserving, quantum-resistant data sharing among heterogeneous blockchain-based CCLSs.